Although adolescent smoking has been a major national concern for many years, there is still relatively little known about its etiology among girls, particularly among young minority girls. While historically smoking rates were greater among males, gender differences in smoking are now virtually non-existent. Studies have demonstrated that at the same level of use, females are more likely to become dependent upon tobacco and are more likely to suffer from a variety of cancers than males, including a greater susceptibility to higher fatality forms of lung cancer. Minority women in particular appear to be at increased risk of developing smoking-related diseases. Therefore, although minority girls demonstrate the lowest rates of smoking during adolescence they may in fact be at highest risk for future smoking and for smoking-related problems. The current project would address existing gaps in the literature in a cost-effective manner through secondary analysis of largely minority, inner-city girls who participated in one of two school-based drug and violence prevention trial (N = 1,138 and N = 1,337). The primary goals of the proposed research are to improve our understanding of how smoking develops among urban minority girls and to examine transitional patterns of smoking behaviors among this population from middle school through high school. Secondary aims of the study are to investigate individual characteristics (i.e., household structure, religiosity, SES, pubertal timing) as potential moderators of the relationship between hypothesized risk factors and smoking as well as to examine relationships between smoking trajectories and indicators of health and well-being among this population. Finally, this study will compare and contrast smoking trajectories by racial/ethnic subgroups as well as examine potential cohort effects. The proposed study represents an important next step in the field of smoking etiology since it examines developmental transitions in smoking behaviors among a severely under-represented population (urban, minority adolescent girls) using state-of-the-art data analytic techniques. Findings from the proposed study will not only advance our understanding of smoking behaviors and transitions among minority girls, but will ultimately help develop and refine prevention efforts for this population and thereby decrease existing gender and racial/ethnic health disparities in the consequences of smoking.